Technologies of dynamically setting a communication path in a communication network include MPLS (“Multiprotocol Label Switching Architecture” E. Rosen and others, RFC3031, IETF) and GMPLS (“Generalized Multi-Protocol Label Switching Architecture” Eric Mannie and others, RFC3945, IETF). Those technologies set a label switched path (LSP) which is a virtual communication path by using a signaling protocol of, for example, GMPLS RSVP-TE (“Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Extensions” L. Berger and others, RFC3473, IETF), in a communication network configured by network devices such as wavelength switches, time-division multiplexers, and packet switches.
As technologies for establishing, when a GMPLS network is configured by multiple layers or multiple management domains, a communication path over the layers or the management domains by signaling, a technique described in JP-A No. 2005-252385 and a technique described in “Preserving Topology Confidentiality in Inter-Domain Path Computation and Signaling”, R. Bradford and others, IETF Internet draft, draft-bradford-pce-path-key-00.txt, Jun. 16, 2006, are known.
According to the technique described in JP-A No. 2005-252385, when a communication path is established by RSVP-TE, a link (that is, a lower-layer communication path) used by each communication path can be determined for each service provided with the use of the communication path. Specifically, a service identifier is assigned in advance to the lower-layer communication path, and an edge node located in the upper layer issues a communication path establishment request which contains the service identifier. A node located at the boundary between the layers selects, from selectable links, a link whose service identifier matches the service identifier contained in the received communication path establishment request.
According to the technique described in “Preserving Topology Confidentiality in Inter-Domain Path Computation and Signaling”, there is provided means for determining, when a communication path is established by GMPLS between a node in a first management domain (hereinafter, referred to as domain 1) and a node in a second management domain (hereinafter, referred to as domain 2), a route of the communication path through cooperation processing performed by managers which are called path computation elements (PCEs) for managing the respective domains.
Specifically, when a source node requests the PCE (hereinafter, referred to as PCE 1) of the domain 1 to calculate the route, the PCE 1 calculates the route of the communication path for a leg (hereinafter, referred to as leg 1) in the domain 1, and then requests the PCE (hereinafter, referred to as PCE 2) of the domain 2 to calculate the route of the communication path for a leg (hereinafter, referred to as leg 2) in the domain 2. The PCE 2 returns key information (path key) corresponding to the calculation result of the leg 2. The PCE 1 returns the route of the leg 1 and the path key of the leg 2 to the source node.
The source node issues a communication path establishment request which contains the route of the leg 1 and the path key of the leg 2. A node located at the boundary between the domain 1 and the domain 2 inquires the PCE 2 by using the received path key to obtain the route of the leg 2 and establish the communication path in the leg 2.